1. Technical domain
The invention mainly relates to an articulation device for an aircraft door panel on a jamb of the said door. This device defines the trajectory followed by the door panel when it opens and closes. It also controls the orientation of the door, so that this orientation is approximately constant when the door is moved along the above mentioned trajectory.
Another purpose of the invention is an aircraft door, particularly comprising a panel and a jamb connected to each other by an articulation device of this type.
A door incorporating an articulation device according to the invention may be used on any type of aircraft. A preferred application is large carriers for passenger transport.
2. State of the art
Conventionally, an aircraft door comprises a jamb connected to the aircraft fuselage and delimiting an opening, usually rectangular, necessary in particular for passengers and the crew to enter and leave the aircraft. The door also comprises a panel connected to the jamb by an articulation device. This device defines the trajectory followed by the panel when it moves between an open state and a closed state. The articulation device also controls the orientation of the door such that this orientation remains unchanged when the door is moved between its open state and its closed state, or vice versa.
An aircraft door also includes locking means that the crew or airport personnel can handle manually to control locking or unlocking of the panel on the jamb, depending on the case.
An aircraft door also includes complementary stops forming part of the jamb and the door panel respectively. When the door is closed, the outside of the panel stops are forced into contact with the jamb stops. Pressurization inside the fuselage helps to maintain the pressure between the stops.
Therefore, before the panel is open following the trajectory defined by the articulation device, the door panel must be moved with respect to the jamb parallel to itself in order to move the panel stops away from the jamb stops. This movement is usually achieved by the use of means of locking the door along the direction in which it will be released. Normally, the door panel is then moved upwards following the curvature of the fuselage and its effect is to offset the stops formed on this panel with respect to the stops fixed on the jamb along the same direction.
As illustrated particularly in document U.S. Pat. No. 5,289,615, an articulation device for an aircraft door panel usually comprises a single arm with a crank towards the inside of the aircraft. This arm is articulated at its first end on the door jamb and at its opposite end on the door panel.
In document U.S. Pat. No. 5,289,615, the articulation device also comprises a door orientation system including a notched belt, a cable or an endless chain installed on the arm. More precisely, the notched belt, and the cable or the endless chain passes between the pulleys or toothed wheels installed on hinge pins centered on the articulation axes connecting the arm to the jamb and to the door panel respectively. Pulleys or guide rollers are also installed on the cranked part of the arm so that the notched belt, cable or endless chain can approximately follow the contours of the arm.
This system is completed by connecting rods that connect each of the hinge pins installed on the ends of the arm to the jamb and the door panel respectively.
In this type of aircraft door panel articulation device, the trajectory followed by the panel when it is opened or closed is circular. Consequently, whenever the door panel starts to move towards the outside of the fuselage, it also moves forwards or backwards parallel to itself, in a proportion that increases quickly as the door panel moves away.
On most aircraft, an emergency exit chute is provided in the folded state in a compartment provided for it in the bottom of the door panel on the inside of the aircraft. This compartment forms a projection, the dimensions and shape of which depend on the size of the chute and the need to prevent any interference between the door panel and the jamb when the door is opened and closed.
On a very large carrier such as an aircraft with two superposed decks, some doors have to be fitted with very long chutes. This is the case particularly for doors on the upper deck, for which the chutes have to be sufficiently long to allow for the height of the upper deck above the ground in the case of an accident. The volume occupied by this type of chute in the folded state makes it necessary to place compartments in the bottom of the corresponding doors that are sufficiently large so that it is almost impossible to install them on a door fitted with a traditional articulation device particularly like that illustrated in document U.S. Pat. No. 5,289,615. Regardless of the shape of the compartment, the circular trajectory imposed by the articulation device inevitably causes interference between the compartment fitted in the door panel and the door jamb during opening and closing operations.
Furthermore, due to the curvature of the aircraft fuselage at the upper deck of a very large carrier with two superposed decks, the upwards movement of the door panel that normally occurs along the curvature of the fuselage by the door locking means to move the door panel stops away from the door jamb stops before opening the door, imposes a relatively large rise distance for the door panel. This rise distance may be as much as approximately 70 mm. This can cause a number of problems that are not found in existing aircraft doors, in which this displacement is significantly smaller.
The purpose of the invention is precisely an articulation device for an aircraft door panel with an innovative design that enables the said door panel to be opened and closed without any risk of interference with the door jamb even if the door panel has to carry a particularly large compartment used to house a chute, with very large dimensions in the folded state.
According to the invention, this result is achieved by means of an aircraft door panel articulation device on a jamb of the said door, the said device comprising a mechanism connecting the jamb to the panel to define a displacement trajectory of the said door panel outside the aircraft when it is opened and closed, and orientation means capable of maintaining an approximately constant orientation of the panel during its displacement along the said trajectory, characterized in that the said mechanism defines a trajectory with a variable curvature comprising mainly a first part with a relatively large radius of curvature approximately perpendicular to the panel including a closed state of the said panel, and a second part with a relatively small radius of curvature approximately parallel to the said panel, including a fully open state of the panel.
In a preferred embodiment of the invention, the mechanism connecting the jamb to the panel defines an approximately elliptical trajectory, in which the major axis is approximately perpendicular to the door panel.
Consequently, the mechanism advantageously comprises a main arm that may be articulated onto the jamb by a first axis, at least one secondary arm articulated on the main arm by a second axis and that may be articulated on the door panel by a third axis, and at least one control lever that may be articulated on the jamb by a fourth axis close to the first axis and articulated on the secondary arm by a fifth axis close to the second axis.
In this case, the fourth axis is preferably offset towards the outside of the aircraft from the first axis and the fifth axis is offset towards the outside of the aircraft and towards the first axis from the second axis.
Preferably, the offsets between the first and the fourth axes and between the second and the fifth axes are approximately equal.
Advantageously, the length of the control lever is then less than the length of the main arm by approximately the same distance as the offsets between the first and the fourth axes and between the second and the fifth axes.
In the preferred embodiment of the invention, the means of orientation of the door panel advantageously comprise at least one first connecting rod, one end of which is fixed to a first hinge pin on which the main arm is supported around the first axis, and the other end of which can be articulated onto the jamb, at least one second connecting rod one end of which is fixed to a second hinge pin installed and free to rotate on the secondary arm about the third axis and the other end of which can be articulated on the door panel, and synchronous connecting means inserted between the first hinge pin and the second hinge pin in order to keep the angular orientation of the second hinge pin constant.
In particular, the synchronous connecting means may include at least one first endless belt supported on the main arm and passing between the pulleys, one of which is connected to the first hinge pin and the other to a third hinge pin installed free to rotate about the second axis, and at least one second endless belt supported on the secondary arm and passing between the pulleys fixed in rotation to the third and second hinge pins respectively.
To facilitate the door opening movement, the main arm is usually cranked towards the inside of the aircraft. It then advantageously supports a fourth hinge pin rotating on the cranked part. In this case, at least two first endless belts pass between the pulleys supported on the first and fourth hinge pins, and between the pulleys supported on the fourth and third hinge pins.
Another purpose of the invention is an aircraft door comprising a jamb connected to the aircraft fuselage and a door panel articulated on the jamb by an articulation device like that defined above.
Normally, the door panel and the jamb comprise complementary stops that come into mutual contact when the door panel is in its closed state. Furthermore, the door comprises locking means that lock and release the door. These locking means are advantageously capable of controlling a downwards movement of the panel to move the panel stops downwards with respect to the jamb stops when the locking means are released before the door panel is opened along the above mentioned trajectory, and vice versa, in order to reduce displacements and simplify the mechanisms.